K2-33b Is the Youngest Exoplanet Ever Discovered

Astronomers just found the youngest exoplanet ever detected.

Dubbed K2-33b, the planet is just 5 to 10 million years old, according to NASA. To put that into perspective, the Earth is about 4.5 billion years old. Its age makes K2-33b one of just a handful of newborn exoplanets we've discovered.

"The newborn planet will help us better understand how planets form, which is important for understanding the processes that led to the formation of Earth," Erik Petigura, co-author on the new study describing the planet, said in a statement.

Astronomers estimate the planet is a little larger than Neptune, and it's locked into a tight orbit around its star. It only takes about five days for the planet to complete a lap. That's about 10 times closer than Mercury is to the sun.

Astronomers aren't sure how planets end up so close to their stars. Some think it takes millions of years for them to migrate into such a tight orbit. But K2-33b's young age is proof that can't always be the case.

"The question we are answering is: Did those planets take a long time to get into those hot orbits, or could they have been there from a very early stage?" Trevor David, lead author on the study, said in the statement. "We are saying, at least in this one case, that they can indeed be there at a very early stage."

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